Update dockerfile to start supporting multi-arch builds

Author: AjayJagan

Dockerfile

@@ -1,25 +1,7 @@
 # Build the manager binary
+FROM registry.access.redhat.com/ubi9/go-toolset:1.23 AS builder
 
-# BEGIN -- workaround lack of go-toolset for golang 1.23
-ARG GOLANG_IMAGE=docker.io/library/golang:1.23
-FROM ${GOLANG_IMAGE} AS golang
-
-FROM registry.access.redhat.com/ubi8/ubi@sha256:fd3bf22d0593e2ed26a1c74ce161c52295711a67de677b5938c87704237e49b0 AS builder
-ARG GOLANG_VERSION=1.23.0
-
-# Install system dependencies
-RUN dnf upgrade -y && dnf install -y \
-    gcc \
-    make \
-    openssl-devel \
-    git \
-    && dnf clean all && rm -rf /var/cache/yum
-
-# Install Go
-ENV PATH=/usr/local/go/bin:$PATH
-
-COPY --from=golang /usr/local/go /usr/local/go
-# End of Go versioning workaround
+ARG TARGETOS TARGETARCH
 
 WORKDIR /workspace
 # Copy the Go Modules manifests
@@ -32,11 +14,9 @@ RUN go mod download
 COPY main.go main.go
 COPY pkg/ pkg/
 
-# Build
-USER root
-RUN CGO_ENABLED=1 GOOS=linux GOARCH=${GOARCH} make go-build-for-image
+RUN CGO_ENABLED=1 GOOS=linux GOARCH=${TARGETARCH:-amd64} make go-build-for-image
 
-FROM registry.access.redhat.com/ubi8/ubi-minimal:8.8
+FROM registry.access.redhat.com/ubi9/ubi-minimal:latest
 WORKDIR /
 COPY --from=builder /workspace/manager .